Answer: Collecting duct to increase water reabsorption.
- A Glomerulus to increase the overall rate of filtration
- B Collecting duct to increase water reabsorption
- C Loop of Henle specifically, bypassing the collecting duct
- D Urinary bladder directly, increasing its muscular tone
Correct answer: B. Collecting duct to increase water reabsorption
Explanation: ADH (vasopressin) increases water permeability of collecting duct and distal tubule by inserting aquaporin channels. More water reabsorbed, concentrated urine produced.
Filtrate flows through four functionally distinct stages of the nephron: Bowman's capsule filters blood, the PCT reabsorbs most useful substances unconditionally, the Loop of Henle builds a concentration gradient via counter-current exchange, the DCT secretes selected substances, and the collecting duct performs the final ADH-controlled water reabsorption.
Concept context
Nitrogenous waste, kidney structure, urine formation in the nephron, and hormonal regulation of excretion.
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